I can increment integers in Vim using <Ctrl>-a. The docs seem to say that if I set nrformats to "octal,hex,alpha" (which I am trying to do with :set nrformats="octal,hex,alpha") then <Ctrl>-a will increment a to b, 007 to 010, and 0x09 to 0x0f, but those examples are not working for me (I just a get a beep for a, 007 turns into 008, and 0x09 turns into 0x10).